The present invention relates to a measuring instrument and a method of measuring, by means of the instrument, an existing pain experienced by a patient.
When a person in need of medical treatment first comes into contact with a doctor, a physiotherapist, a nurse etc., this person generally tries to describe his pain verbally, so that the medical staff are at least able to make a primary diagnosis of the patient""s condition and suggest a suitable treatment. However, this creates a significant problem for the medical staff, depending upon different persons experiencing, and therefore describing, their pain or symptoms in different ways. One person may e.g. be more resistant to pain than others. Another person may e.g. have become used to his pain after a certain period of time and may therefore describe his/her pain in milder terms than he/she would have done if the pain had arisen recently. The varying descriptions of pain which a diagnostician may be exposed to complicate a quick and exact diagnosis of a person""s ailment or injury.
For the sake of simplicity, in the below text the patient is always referred to as being male. It should of course be understood, however, that the same applies to female patients.
In order to hitherto measure pain in patients, doctors, physiotherapists etc. use a so called measuring rod or ruler; this technique is called Visual Analogue Scale (VAS). The general design of a measuring rod having a VAS scale is shown in FIGS. 1 and 2. There is, however, a variety of different designs of this measuring rod, but their function is generally the same and will be described with reference to FIGS. 1 and 2.
As can be seen from FIG. 1, the measuring rod is divided into grades from e.g. 0-10, where xe2x80x9c0xe2x80x9d means no sensation of pain and where xe2x80x9c10xe2x80x9d means unbearable sensation of pain or worst possible sensation of pain. FIG. 2 shows the reverse side of the measuring rod of FIG. 1, and during a measurement the patient will only see this side.
Suppose a patient having a pain in his arm goes e.g. to a doctor. The doctor picks up his ruler (measuring rod) and asks the patient if he can describe his sensation of pain by placing his finger on that spot on the ruler which best corresponds to the sensation of pain in his arm. The doctor has of course previously explained to the patient how the ruler functions, i.e. that one end A of the ruler corresponds to no sensation of pain and the other end B of the ruler corresponds to an unbearable sensation of pain (FIG. 2).
Assume that the patient places his finger on the ruler at a value of xe2x80x9c7xe2x80x9d on the pain scale (0-10). The scale on the ruler is turned towards the doctor so that only he can see the pain scale (FIG. 1) and the patient can only see the reverse side of the ruler as shown by FIG. 2.
The doctor thus quickly obtains information about how the patient at present subjectively experiences the pain in his arm.
The doctor then prescribes a treatment for the patient, e.g. some kind of painkiller.
When the patient comes for his next visit to the doctor, the same procedure with the ruler is repeated, and the patient now places his finger at a location on the ruler which e.g. corresponds to the value xe2x80x9c2xe2x80x9d on the pain scale (0-10).
The doctor thus obtains an indication that the pain in the arm has decreased by comparing the previous value of xe2x80x9c7xe2x80x9d with the present value of xe2x80x9c2xe2x80x9d. Thus, the doctor can conclude that the treatment has been effective.
If the patient during his next visit instead places his finger at a location on the ruler which e.g. corresponds to the pain value of xe2x80x9c8,5xe2x80x9d, the doctor can instead determine that the previous treatment has been ineffective, and he can therefore act accordingly; e.g. prescribe a new medicine or a referral to a physiotherapist, a masseur etc. The doctor thus uses the measuring rod to determine whether a treatment has been effective or not.
One problem with this ruler according to FIGS. 1 and 2 is that the patient must consciously think about and evaluate where to place his finger on the ruler, between the values no sensation of pain and unbearable sensation of pain, as shown in FIG. 2. The patient is all the time aware of, that the closer he places his finger in relation to the end A of the ruler, i.e. no sensation of pain, the less pain he is supposed to sense, and the closer he places his finger in relation to the end B of the ruler, i.e. unbearable sensation of pain, the more pain he is supposed to sense. This awareness of the patient is just what the present invention eliminates.
Another problem with the ruler according to FIGS. 1 and 2 is that the doctor cannot objectively verify the pain value given by the patient; the patient may e.g. lie about his sensation of pain and place his finger at the same pain value at different measurement occasions.
A further problem with the ruler according to the FIGS. 1 and 2 is that different persons sense pain in different ways.
Some persons can stand pain better than others and will describe their pain with a low value (e.g. xe2x80x9c2xe2x80x9d) on the ruler; other persons have a low pain threshold and will describe the same pain with a high value (e.g. xe2x80x9c9xe2x80x9d) on the ruler.
The present invention also eliminates this problem.
In order to find out if the previous art solves the problems mentioned above, a pre-study was performed, whereby the following documents were found.
The document EP,B1 0 438 541 describes a portable instrument performing a multidimensional indication of pain sensed by a person. The portable instrument has indicators that may be adjusted by a person to provide a physical indication of the type of pain intensity being sensed by said person.
The document U.S. Pat. No. 4,641,661 describes an electronic meter for determining the pain threshold for a pressure applied to the skin surface of a patient. The pressure is increased until the patient presses a button when he/she senses pain. The pressure achieved is registered.
The document U.S. Pat. No. 4,697,599 describes a device for localisation and detection of pain by measurement of the conductivity of the tissue.
The document U.S. Pat. No. 5,020,542 shows a method for measuring the sensibility of the skin of a patient to electrical stimulation.
The document JP,7 023 964 describes a method for measuring pain objectively and quantitatively.
The document GB,2 049 431 describes a so called measuring rod for providing a subjective measurement of the pain sensed by the patient.
The documents found do not solve the problems mentioned above.
Thus, the object of the present invention is to solve the above problems.
Another object of the present invention is to allow an objective way of performing the pain measurement.
Yet another object of the present invention is to provide a measurement value of pain which is relevant for comparison between different patients.
A further object of the present invention is to provide a portable, very easy to use, measuring instrument for the measurement of pain.
Yet a further object of the present invention is to allow the doctor, the physiotherapist etc. to feel and sense the patient""s pain, which has a psychological significance that may entail a shortened time for medical care of the patient, as the patient feels he has been understood.
These objects are achieved by a device and a method according to the characterizing parts of the appended patent claims, respectively.
Advantageous embodiments of the present invention are described in the dependent claims.